我正在努力制作康威的生活游戏，但我在使用repaint()方法时遇到了问题。我创建了一个扩展JPanel的类，当我覆盖绘制时我调用super.paint(g)，而且我没有覆盖repaint()方法，但我没有运气。我在这里测试的主要方法是（请原谅我可怕的标识符）：
import javax.swing.JFrame;
public class YouThinkThisIsAGame extends JFrame {
private Life facebook;
public YouThinkThisIsAGame() {
super("I'm Blue da ba dee da ba die");
Life kyle = new Life();
add(kyle);
//setSize(kyle.getALife()[0].length * 5, kyle.getALife().length * 5);
setSize(500, 500);
setVisible(true);
setMaximumSize(getSize());
setMinimumSize(getSize());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
YouThinkThisIsAGame stuff = new YouThinkThisIsAGame();
while (true) {
stuff.facebook.repaint();
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
JPanel扩展课程在这里：
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JPanel;
public class Life extends JPanel {
private Cell[][] grid;
Color life;
{
life = new Color(0, 175, 0);
initializeGrid(1300, 800, 0.025);
}
public void paint(Graphics G) {
super.paint(G);
Graphics2D g2d = (Graphics2D) G;
drawGrid(g2d);
}
/** Me attempting to be funny */
public String getLife() {
return null;
}
/** Also trying to be funny */
public Cell[][] getALife() {
return grid;
}
public void drawGrid(Graphics2D g) {
for (int i = 0; i < grid.length; i++) {
for (int j = 0; j < grid[i].length; j++) {
if (grid[i][j].isLiving) {
g.setColor(life);
//g.setColor(Color.WHITE);
} else {
g.setColor(Color.BLACK);
}
g.fillRect(i * 5, j * 5, 5, 5);
}
}
}
/** Allocates a new grid of cells of the requested dimensions and
* sets each cell in the grid to a random living/dead state.
* The desired percentage of living cells is passed as a
* parameter.
*
* @double percent roughly, the percentage of cells that should
* be initialized as alive
*/
public void initializeGrid(int rows, int cols, double percent) {
grid = new Cell[rows][cols];
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
grid[i][j] = new Cell();
double x = Math.random();
if (x > percent) {
grid[i][j].setLiving(false);
} else {
grid[i][j].setLiving(true);
}
}
}
}
/** Displays the contents of the grid to the standard output.
*/
public void displayGrid() {
for (Cell[] cellRow : grid) {
for (Cell c : cellRow) {
if (c.isLiving()) System.out.print("0");
else System.out.print("1");
}
System.out.println();
}
}
/** Updates the value of each cell in the array according to
* the rules of life:
* If the cell is currently living --
* if fewer than two neighboring cells are alive, die (loneliness)
* if two or three neighboring cells are alive, live
* if four or more neighboring cells are alive, die (overcrowding)
* If the cell is currently dead --
* if precisely three neighboring cells are alive, become alive
*/
public void updateGrid() {
Cell[][] gridCopy = new Cell[grid.length][grid[0].length];
for (int i = 0; i < grid.length; i++) {
for (int j = 0; j < grid[i].length; j++) {
Cell c = new Cell();
c.setLiving(grid[i][j].isLiving);
gridCopy[i][j] = c;
}
}
for (int i = 1; i < grid.length - 1; i++) {
for (int j = 1; j < grid[i].length - 1; j++) {
int adjacentAlive = 0;
if (i == 2 && (j == 4 || j == 3)) {
System.out.print("");
}
if (i == 3 && j == 4) {
System.out.print("");
}
if (gridCopy[i - 1][j - 1].isLiving) {
adjacentAlive++;
}
if (gridCopy[i][j - 1].isLiving) {
adjacentAlive++;
}
if (gridCopy[i + 1][j - 1].isLiving) {
adjacentAlive++;
}
if (gridCopy[i - 1][j].isLiving) {
adjacentAlive++;
}
if (gridCopy[i + 1][j].isLiving) {
adjacentAlive++;
}
if (gridCopy[i - 1][j + 1].isLiving) {
adjacentAlive++;
}
if (gridCopy[i][j + 1].isLiving) {
adjacentAlive++;
}
if (gridCopy[i + 1][j + 1].isLiving) {
adjacentAlive++;
}
if (adjacentAlive == 3) {
grid[i][j].setLiving(true);
}else if (adjacentAlive == 2) {
} else {
grid[i][j].setLiving(false);
}
}
}
System.out.println("");
}
/** Convenience method for setting the grid values.
*
* @param grid a two dimensional table of Cells
*/
public void setGrid(Cell[][] grid) {
this.grid = grid;
}
public static void main(String[] args) {
Life life = new Life();
life.initializeGrid(15, 40, 0.25);
life.displayGrid();
while (true){
try {
Thread.sleep(250);
} catch (InterruptedException e) {
e.printStackTrace();
}
life.updateGrid();
life.displayGrid();
}
}
class Cell {
private boolean isLiving;
public void setLiving(boolean isLiving) {
this.isLiving = isLiving;
}
public boolean isLiving() {
return isLiving;
}
}
}
答案 0 :(得分：2)
你有两个主要方法，我假设你运行的是YouThinkThisIsAGame类中的方法。如果是这样，你永远不会从这个main方法调用Life对象上的updateGrid()（但你在其他 main方法中），所以网格永远不会更新。
建议：
while (true)循环的Runnable。updateGrid()
repaint()。start()。super.paintComponent(...)。@Override注释，让编译器检查您实际上是否覆盖了该方法。facebook字段，而是使用在YouThinkThisIsAGame构造函数内部声明的影子变量kyle。这是唯一可行的Life实例。updateGrid()和repaint()生活实例（这就是为什么我上面提到的可视化 - 这是关键）。import javax.swing.JFrame;
public class YouThinkThisIsAGame extends JFrame {
private Life life; // renamed to life
public YouThinkThisIsAGame() {
super("I'm Blue da ba dee da ba die");
// no -- don't create a new Life variable!
// Life kyle = new Life();
// add(kyle);
life = new Life(); // initialize and use the **field**
add(life); // and place it into the JFrame
setSize(500, 500); // better to have Life override getPreferredSize
setVisible(true);
setMaximumSize(getSize());
setMinimumSize(getSize());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void updateLife() {
life.updateGrid();
life.repaint();
}
public static void main(String[] args) {
final YouThinkThisIsAGame stuff = new YouThinkThisIsAGame();
new Thread(() -> {
while (true) {
stuff.updateLife();
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}).start();
}
}